OldMetMan
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Posts posted by OldMetMan
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Old man met, i remeber 1980s winters and they were pretty bad , well good.
There is a heavy band of precipiation off cornwall at present and at the moment this doesnt look like just skirting with southern most cities on south coast as forecast for monday. Any chance that this could continue on its,current path and affect the whole of the southwest tomorrow?
The cyclonic circulation is quite complex at the moment with today's LP gradually being absorbed into a developing LP to the SW. It depends where you are located as coastal areas will I believe still be marginal. I would be inclined to carefully watch what subsequent LPs develop upstream in the next few days heading your way. Particularly keep in mind wind direction - any switch to an onshore flow as opposed to what we are getting now could make a very big difference as to whether it's snow or rain.
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You know much more than I... but the other lurking frustration with this winter is that we havent really seen any proper blocking. Anomalies have suggested it, but we have been in the back pocket of the Canadian Vortex most of the winter, with nothing more than the current deflections to write home about. GP got my hopes up in November with talk of high lat blocking, negative NAO along with the negative AO and a particularly blocked late Jan/early Feb. Right now I cant see where it is going to come from precisely because of your comment on winters tending to feature repeating patterns. I see another week or two of atlantic dominance followed perhaps by height rises over Canada encouraging a potentially early spring.
It has been an interesting winter of cold zonal so far overall - that didnt worry me too much in the early stages as for the SW that suggested big snowfall... but that has not happened. Seems we need to have a big block in place after all to get the really cold air in place first. This marginal stuff is just... well... too marginal. Quite why there was so little precipitation on Friday after the absolute drenching the SW has had from every other front that has been inbound this winter I dont know. It wasnt that it rained - it just didnt snow enough. Guess that was just back luck.
Back to my reports. Wish they were as fascinating as interpreting hemispheric weather patterns!
I take your point certainly, it's not been spectacular! However, the flow as it has been recently has been anomalous. I base much of what I say in this regard from historical patterns rather than specific atmospheric indicators which I have to admit I know little about. However, I have seen a lot of weather and, as in other walks of life, one gets "gut feelings" as to what may happen, without necessarily having any hard evidence to back it up! Not always right, for sure but occasionally!
Anyway, good luck with your reports!
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Oldmetman, how much snow did the s.w actually get back then? Thanks om.
Hi offerman, I have just done a quick post of my own experience of it, but snow drifts of 20 - 30 feet occurred and cars, trains etc were literally buried, especially over places like Dartmoor and Exmoor.
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A fascinating look at an incredibly severe winter: Intense cold with sea, canals and rivers entirely freezing. Roaring blizzards on an epic scale with 90 mph gusts and people being caught in their vehicles and suffocating to death. Monumental drifts even half burying racecourse stands etc. Stuff that, although in living memory, is still beyond belief for here in Britain but it happened nevertheless and we should be aware that it will happen again!
Quite so! I witnessed it first hand - I lived on the Isle of Wight - and saw snow drifts of 2-3 metres or more a mile or so from where I lived, plus snow was on the ground in our front garden from Boxing Day 1962 to the first week in March 1963!
Not that long ago, a certain meteorologist proclaimed that snow was becoming a thing of the past in this country! I think he is eating his words now.
Sorry mods for wandering off topic but I think it's important, especially the younger members who have not seen it for themselves, to realise what CAN happen here in winter!
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Born in 1970 so no - but I am aware of the snow possibilities here and the channel low scenario. That is what made Friday so personally frustrating - there was just so little precipitation it was unreal. I hope that there is indeed a good bit of winter left - this week may yet deliver the goods though there is a greater westerly influence entering these slider lows now so I see rain. Beyond that my analysis - flawed though I hope it is - is telling me we may have to wait a good bit for some kind of pattern reload after the atlantic wins at the weekend.
I do understand. Friday was a far stranger event than many realise, especially for those of us living on the coast, where with S or SE winds it too often just rains. Instead the extremely low dewpoints over France were drawn towards the frontal zone at such speed, it was all snow. Never seen that before. But the longer sea track in your part of the world clearly made a difference.
There are many odd features to this present cold spell, not least of which is that it isn't actually that cold! Seems an odd thing to say but the thickness values have been hovering around 528 throughout, unlike say 2010 when they got down to 516 and below - that IS cold. But, all credit to the Met for the accuracy of their snow distribution forecasts.
Blocked patterns do tend to repeat - that is something I have seen happen so often in the past - so I put my faith in that observation this time around!
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Not in the SW it isnt... hence the worries over the medium and long term. We have cold air but very little snow. A good many have had none so far.
I wonder if you saw the fascinating documentary about the 1963 winter on BBC2 last night? I don't know if you are of the generation that experienced it, but when the SW DOES get snow, it can get it on a phenomenal scale as happened back then. Plenty of winter left yet for everyone to get their fill of snow!
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This is becoming one of the most interesting winter weather scenarios I have seen for a long time, made even more interesting by the way the models are handling it!
At present, the models seem to agree on a return to Atlantic weather within a week or so. Interestingly, the GFS backed off a bit on the 12Z run and the GEM has been the slowest to break down the block. But, as ever, the degree of certainty I would call very low indeed in the mid- to long-term, given the chopping and changing we've had recently.
The 500mb flow is particularly interesting. The guidance coming from the US has been mentioning the upper ridge over the E Pacific quite a lot, and the fact that the models are collapsing it with renewed cyclonic activity entering the Pacific NW. At the moment, the ridge is showing no signs of going anywhere:
This predicted collapse seems to be the key to changing the pattern downstream. The Canadian vortex has most of it's energy well to the E and SE, the collapse of the Pacific ridge would likely allow it to return further W as the predicted cyclonic development moves in and joins it.
Meanwhile, there is a persistent upper high to our N and an extended upper trough running to its S well SE almost to N Africa, hence the succession of LPs sliding SE into the Mediterranean. The remarkably persistent weakish HP to our N associated with the upper high is showing no signs of immediate change. It is an offshoot of the Arctic HP which is still feeding cold air SE into Europe.
Historically, these patterns can be VERY persistent and it is clear the models are pretty hopeless at predicting their development beyond the short range. On that basis, I am putting very little trust in anything beyond T+96 at the moment. The overall upper long wave pattern looks very stable to me so I see no immediate reason for it to change.
The jet has spread a little further E but it still is running on quite a low latitude so unless and until the US pattern changes as described above I don't foresee any big shift in its trajectory and thus the UK remaining in the cold air, although we may see some less cold air pushing into southern counties for a bit, before the north-easterlies reassert themselves.
So, the snow risk remains for the foreseeable future as far as I am concerned. One major concern I have if milder air does filter into the south of the country is the potential for freezing rain, but I hope I am wrong on that score!
All in all, a fascinating week's weather - and model watching - ahead!
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Sorry but still new to this if the low head south would that mean all the snow would come back and continue through the night
Not very likely I'm afraid, will most likely drift NW, but there is another LP coming in from the SW which will probably absorb the LP moving across the SE. Where the snow will be is going to be very difficult to forecast in the coming days.
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Is this on the METO website mate or was it created by yourself? Cheers.
There remains some uncertainty on snow totals and the extent of the snowfall to the South and close to coastal areas, it's likely that precipitation will fall as rain and sleet initially across Devon, South Somerset, South Dorset and Coastal Hampshire, but as the cold air undercuts later it's likely to turn increasingly to snow - giving accumulations.
As I mentioned earlier, there is the added risk of freezing rain if we get a shallow, slightly warmer feed off the Channel along the coast. I hope I'm wrong!
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Thanks OMM, good to see in here again. Thankyou for your sound analysis too.
Thanks GTLTW, been studying the wider picture trying to figure out what on earth we can expect this coming week with the confusing model outputs!
One form of precipitation I didn't mention was of course freezing rain/drizzle, I fear that's a possibility too in the coming days - deadly stuff I hope it doesn't come to that!
Temp here is now dropping back - down to about 0.5C, nearly had some sunshine an hour or so ago. Offshore winds are pulling the cold air down into this area at present, but with the new Atlantic system slowly edging NE towards us, I guess it's possible we might start to pick up a light drift off the Channel - that sort of situation is when freezing rain becomes a possibility. I shall need my spiked boots if that happens!
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Afternoon folks!
Bit of a messy picture here in Southampton, started light snow around 9.15 but it's all but stopped, perhaps just about 1cm on the car windscreens. Pavements very treacherous with a thin layer of new snow on top of ice.
Just on the edge of the snow area here, it MAY push back a little further W but most of the movement is NW. I guess those of you in Essex and Kent who missed out Friday might have made up for it a bit today.
Very messy picture of the synoptic front, with a complex LP area swirling around over the country the next few days, we could literally get anything - snow, ice, fog, sleet, frost, snow grains.......I suspect the cold air supply of the near continent may get cut off, at least temporarily, but the surface air over much of the UK is so darn cold, so we might hold onto mostly snow for the time being.
Beyond that, I think if some of the models are to be believed, there is still a risk of more substantial snow later this week, a lot depends on how much our cold pool warms up in the meantime. Still a lot to watch though.
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Maybe it's because of the bombardment from the Atlantic thats stoping the scandy high from building . Correct me if I'm wrong as I'm a newby
There are certainly times when the strength of the Atlantic jet can blow away even strong HP as well as other times when it can help build and maintain them, for example, when the jet heads NE S of Greenland and to the NW of Scandinavia, pushing warm air into that area can build a strong upper ridge in the Norwegian Sea and HP builds over Scandinavia as a result.
I think it does have a lot to do with how intense the European cold is, like I said the thickness values weren't that low, so the resulting HP wasn't that strong. The more cold and dense the cold air is, the higher the pressure. We see this process often over Greenland. What is interesting now is the presence of intense HP over the Pole itself which, in my experience, is not that common, so the Scandinavian HP is an offshoot of this. This makes me think the pattern of HP to the N of us will continue for a while yet, even if Atlantic systems do make some inroads into our area. It suggests the cold air will return first chance it gets.
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Does anyone think that GFS is having problems due to the apparent strength of the Jetstream? It just can't seem to get a grip on working out the fact that the jet is quite strong, but seems to be having very little effect on the Northern latitudes. You could argue that although there isn't really any huge & powerful Northern blocking, from an HP perspective, it is well & truly blocked by the Easterly zonal winds, which are just deflecting any attempt to penetrate into high latitudes. Along with many members I'm amazed that such a feeble & flimsy looking Hp to our North East, has held out so long against what is on the face of it, quite a powerful Jetstream. Thoughts anyone?
I have been wondering myself! Sometimes, I think it's a matter of spacing of the long-waves around the hemisphere which at times keep to the same relative positions, i.e. a static pattern with short-wave features running around them. At other times, the movement of these long-waves is more mobile. I do not understand the reason for this but have noticed it by compiling and watching 500mb animations.
The upper high currently to our N has been around over a week, fading and then re-forming and this, together with a Mediterranean upper low have maintained their position relative to upstream and downstream vortices. Although there has been no really low thickness values over Europe as a whole, the actual cold pool has been very extensive. Surface cooling has given some very low temps in E Europe but with the thickness values being what they have been - not that low- then the HP has indeed been quite a feeble affair. Lower thickness values would I think have provided a stronger HP to the N of the cold pool.
Also, there has been an intermittent trickle of cold polar air heading S near Scandinavia to maintain the cold pool.
The US jet had helped to build our upper HP in the first place by steering LPs NE to the S of Greenland but for the last few days it has stayed over the W Atlantic and is currently keeping a low latitude and even feeding into the sub-tropical jet.
How all these features interact has to be a complex process and certainly one the models have had a hard time predicting beyond a certain point. I suppose you could look at it this way: the atmosphere is a fluid and, like water in rivers and streams, will form eddies which sometimes remain and sometimes not, depending on what obstacles it encounters and cold,dense air would certainly count as an obstacle, as does hot and stable air in summer.
When someone finally cracks this riddle, then we can expect a vast improvement in long-term model output!
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It's been quite a day, been over on the regional forum for much of it. I am still marveling at how much snow we got on the coastal strip.
Anyway, all credit to the UKMet, not just from the modeling point of view but for such a accurate assessment of the snowfall. As this cold block seems set to continue, at least for a few days more, then their model will be the one to watch I think. There is little to inspire confidence in accuracy in the GFS, even in the short term and a variety of longer term solutions from the other models.
We do have an uncommon 500mb flow in some respects as is the associated jet. The strong US jet is taking a more southerly turn as I suspected last time I posted and the flow over much of the central and northern Atlantic remains quite weak.
At 500mb, the small upper high has returned to our north with an upper low over the UK, still extending SE into the Mediterranean. Further west, the large Canadian vortex is showing signs of extending eastwards and I strongly suspect that heights will build to the N of this.
The net effect suggests to me a continuation of the blocking pattern. It is interesting to note that the HP to our N and NE is an extension of quite a strong Arctic HP so cold air continues to filter S into Europe - another factor I think will maintain the blocking pattern.
This current configuration has some interesting similarities to past severe cold spells, such as 1947 when repeated Atlantic attacks were repelled by the block with some outstanding snowfalls happening as a result. The GFS keeps trying to warm things up but then revises on the next run or two.
I think day to day variations will be complex as Atlantic systems come near, as will the distribution of any snowfall. But the details will be most interesting to watch. Who knows, maybe 2013 will be a year we'll talk about for years to come!
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Just to put today's snow into perspective, at least in my part of the world, today has been the 3rd heaviest snowfall since I have lived here, namely 31 years, only surpassed by January 1982 (about 10cm) and December 2010 (15cm).
Those of you who watch the model output will realise that it's all not over yet. The upper air circulation is peculiar to say the least, and there are, in my view, still some strong signs that this cold blocking pattern will persist, yes maybe breaking down slightly at times, but it has some striking similarities to past notoriously cold past winters, in particular, 1947 (no I don't remember it first-hand, not quite that old!).
So, for those of you who missed out today, there is still further scope for future falls so - be careful what you wish for!
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Is the band going to head back west ?
I think the synoptic situation is more complex, as the earlier FAX charts show. There is still some NE momentum showing on satellite into East Anglia and the NE but this has stopped further to the NW. As others have pointed out, the frontal zone(s) seem to be breaking up in situ. So as I see it, as the LP develops W of Portugal and heads NE, our LP will get absorbed into its circulation as a trough and the frontal system, well, it's southern part, whatever is left of it, will slowly fizzle out altogether, its remnants sinking S or SW.
The snow is easing where I am, very fine and granular suggesting the dewpoints are falling.
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Snow is now bordering on heavy and temp is dropping back. Depth between 5cm and 6cm.
I was just looking at temps to the N and E of us, over the Home Counties and Sussex, which are actually falling, -2 and -1s reported widely. Even St. Catherine's point on the IOW is 1deg.
I haven't been through all the many posts but I was wondering what the snow situation is like on the Island.
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I truly have never seen anything like this!
Right now, temp around 0.5C, we have nearly every form of ice precipitation falling - snow, snow pellets, ice pellets even a few snow grains - truly amazing.
I cannot emphasise enough how remarkable the way this snow situation developed is. From temps of over 3C in the early hours of this morning to this. I said so earlier, but I must sing the praises of the Met Office for getting the warnings so accurate. Plus I again apologise for questioning those warnings as I did yesterday.
Since I started this post, it is now snowing harder again. I estimate snow depth now 5cm.
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Still moderate snow here, snow depth around 4cm, maybe 5cm in places. Temp slightly above freezing now as it is starting to drip outside.
Looking at the satellite, it looks as if the frontal zone is nearing it's stalling point. The cloud pattern suggests it will shear apart gradually, with the northern part pulling away to the N whilst the southern portion will slowly sink away to the SW. So the snow looks set to continue over the SE, into the Midlands and Wales but with decreasing intensity as the day goes on.
Think I will go and get a paper before the snow turns to slush on the pavements!
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Morning folks, and a fine snowy morning it is too! Here, about 4cm snow, temp around freezing or just below.
First, my unreserved apology to the Met Office for questioning their severe weather warning. There were absolutely on the money and I take my hat off to them!
In all my years, I have never seen a snow situation develop in this way - I really did not think it possible! There is always something new to learn about the weather that is why I have been so fascinated by it over so many years.
It's eerie here right now, it's quieter outside than Christmas Day, seems people have actually heeded the warnings.
I expect the snow will gradually ease, there is no sign of it thawing at the moment. Even the roads are covered.
Great stuff!
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I've just been watching the IR satellite animation on Sat24, very interesting, looks as if the occlusion process will soon be complete. The split flow is very evident now, the frontal zone is approaching the axis of the 500mb ridge, this is where it gets interesting. Can't see any sign of a surface circulation forming yet, but these are hard to see in IR imagery.
In weather terms, it seems as if the Irish Sea or the Bristol Channel (most likely the latter) is where the surface low could form That would explain the Red Warning for S Wales so that will doubtless intensify the snow to its east.
I'll just wait for the 0100 surface chart then off to bed!
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I'm starting to wish this detritus currently over more central parts would bugger off.
Is this simply going to be pushed out of the way, its bloody just keeping my Temps up for now, I'd prefer clear skies.
0.6c AT, -0.2c DP, 1010.2mb rapidly falling barometer trend.
The satellite shows the old front responsible is shearing apart, so the southern part is fizzling out as the main frontal system approaches.
It's kind of weird here at the moment, the rain has stopped just about, temp around 3.1, humidity up (don't trust the hygrometer in this thing either!) but the wind is gusty and like you the pressure is falling quite quickly. But there is a distinct chill to the wind, suggesting the lower dewpoints are arriving.
Best go to bed soon I suppose - I'll be listening for slushy noises from the road outside before I get up!
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That's weird - my road only has them on one side as well! The other side is a tree-lined school field and it's very dark over there. The extra height of the new posts do seem to direct the light into bedrooms more than the old ones did.
I asked the men when they were installing them why they were only on one side, he said the council thinks they are bright enough to light both sides of the road. Yes, we get the light in our bedroom too - my wife thinks they have cameras installed in them!! Wouldn't be surprised!
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I miss my old lamp. RIP Lampie.
Indeed, our mean council have only put them on one side of the road too - right opposite my house!
Winter Model Discussion 18Z 19/1/13 onwards.
in Spring Weather Discussion
Posted
What I was saying relates to thickness values which have been around the threshold where one starts talking about snow - 528dm. I'm not denying the low maxima and minima that have occurred.